The present invention relates to a flywheel assembly, and particularly to a flywheel assembly comprising a first flywheel, a second flywheel, and a viscous damping mechanism located between the flywheels.
Compound flywheel assemblies for automobile engines are in current use. Such a flywheel assembly typically comprises first and second flywheels, with a viscous damping mechanism disposed between them. The first and second flywheels are rotatably connected to each other through a bearing. The second flywheel has a friction facing onto which friction material or a clutch disc presses.
Lubricant is sealed within the bearing disposed between the flywheels. However, prolonged operation deteriorates the sealing ability therein, such that lubricant can leak out and reach the friction facing of the second flywheel, causing clutch slippage.
The viscous damping mechanism employed in between the flywheels is filled with a fluid such as grease. The fluid may leak through the bearing and/or seals and splash out over the friction facing. Lubricant thus will stick to the clutch, further contributing to slippage problems.
Power from the first flywheel is transmitted through an output plate to the second flywheel. The output plate and the second flywheel are engaged by corresponding geartooth portions. Some grease should flow from the viscous damping mechanism and enter the engagements of the output plate and the second flywheel in order to provide lubrication therein. High operating temperatures, however, thin the lubricant, and furthermore high-speed rotation drives it radially outward, such that the lubricant tends to run short at the engagements, leading to fretting of the gearteeth.
The viscous damping mechanism absorbs torsional vibrations during the transmission of power from the engine, but it cannot, however, absorb bending oscillations which arise at the same time. Such bending oscillations are transmitted to the transmission, resulting in vehicle noise.